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•The effects of two typical S0 allotropes on chalcopyrite bioleaching were studied.•The addition of µ-S promotes Cu leaching rate significantly, while ɑ-S8 inhibits.•Both ɑ-S8 and µ-S ...affect the formation and evolution of secondary minerals.•Cell metabolism is much more changed by the addition of µ-S than ɑ-S8.•The addition of µ-S promotes the adsorption of bacteria on the CuFeS2 surface.
Elemental sulfur (S0), as one of the most important intermediates formed during chalcopyrite bioleaching, can exist in a variety of allotropic forms, among which amorphous μ-S and orthorhombic ɑ-S8 are the most common forms. Although previous studies have focused on the effect of S0 on chalcopyrite bioleaching, how S0 allotropes affect chalcopyrite bioleaching is unclear. Therefore, in this work, the differential effect of ɑ-S8 and μ-S on chalcopyrite bioleaching by Acidithiobacillus ferrooxidans (A. ferrooxidans) was studied at the molecular and atomic levels by combining synchrotron radiation-based X-ray absorption near edge structure (XANES) spectroscopy, comparative transcriptome analysis and density functional theory (DFT) calculations, accompanied by the determination of solution behaviors and mineral surface morphologies. The results showed that µ-S was favorable for bacterial adsorption and that the addition of µ-S could promote the copper extraction rates by A. ferrooxidans, while the addition of ɑ-S8 inhibited the copper extraction rates. The XANES results showed that both cases with the addition of ɑ-S8 and µ-S could affect the formation and evolution of secondary minerals during bioleaching by A. ferrooxidans. The comparative transcriptome analysis showed that the gene expression of A. ferrooxidans was much more affected by the addition of µ-S, with more genes upregulated than ɑ-S8. The DFT results indicated that both ɑ-S8 and µ-S could adsorb on the CuFeS2 (001) surface easily, and µ-S could make the CuFeS2 surface obviously change, while ɑ-S8 hindered the adsorption of bacterial cells. Of note, µ-S could enhance the interaction between the CuFeS2 (001) surface and bacterial cells with stronger bonding and more transferred electrons than ɑ-S8.
The completely autotrophic nitrogen removal over nitrite (CANON) is a new type of nitrogen removal process developed in recent years. The control of dissolved oxygen (DO) in this process is ...relatively stringent, especially in low-substrate wastewater treatment. However, the results of studies on the operation of the process in different aeration modes are still controversial, and investigations on biofilm type CANON reactors are limited. In this study, a pilot-scale CANON bioreactor filled with suspended carriers was investigated on the treatment of wastewater at low ammonium concentrations, and the effect of the aeration mode on autotrophic nitrogen removal was evaluated. Seven conditions with various aeration on/off times and DO levels were tested. The results showed that an intermittent aeration with a 20-min/20-min aeration on/off time and DO concentrations of 1.0–1.3 mg/L at the end of the aeration period was appropriate, potentially inhibiting nitrite oxidizing bacteria (NOB) and keeping the total nitrogen (TN) removal rate at a relatively high level of 76.7% ± 2.5%. In the optimal aeration mode, the reactor achieved effluent TN and NH4+-N concentrations of (11.1 ± 3.3) mg/L and (3.6 ± 2.3) mg/L, respectively, with a hydraulic retention time of 12 h and an influent NH4+-N concentration of (48.6 ± 9.4) mg/L at 30.1°C ± 2.2°C. The results of metagenomic sequencing for microorganisms on carriers indicated that the main nitrogen removal bacteria in the reactor were Proteobacteria, Planctomycetes, and Nitrospirae. The NOB genus Nitrospira was completely inhibited by intermittent aeration. Candidatus Kuenenia had strong adaptability to low-concentration wastewater.
This paper discusses the mean-square exponential stability of stochastic linear systems of neutral type. Applying the Lyapunov–Krasovskii theory, a linear matrix inequality-based delay-dependent ...stability condition is presented. The use of model transformations, cross-term bounding techniques or additional matrix variables is all avoided, thus the method leads to a simple criterion and shows less conservatism. The new result is derived based on the generalized Finsler lemma (GFL). GFL reduces to the standard Finsler lemma in the absence of stochastic perturbations, and it can be used in the analysis and synthesis of stochastic delay systems. Moreover, GFL is also employed to obtain stability criteria for a class of stochastic neutral systems which have different discrete and neutral delays. Numerical examples including a comparison with some recent results in the literature are provided to show the effectiveness of the new results.
For long-distance water conveyance shield tunnels in operation, the high internal water pressure may cause excessive deformation of composite linings, affecting their structural integrity and ...serviceability. However, the deformation and failure characteristics of lining structures under internal water pressure are not well investigated in the literature, particularly for three-layer composite linings. This study presents an in situ experimental investigation on the response of two types of composite linings (i.e. separated and combined lining structures) subjected to internal pressures, in which a fiber optic nerve system (FONS) equipped with distributed strain and displacement sensing nerves was employed to monitor the performance of the two composite linings during testing. The experimental results clearly show that the damage of the tunnel lining under different internal pressures was mainly located in the self-compaction concrete layer. The separated lining structure responded more aggressively to the variations in internal pressures than the combined one. Moreover, two evaluation indices, i.e. radial displacement and effective stiffness coefficient, are proposed for describing the changes in the structural bearing performance. The effective stiffness coefficients of the two types of lining structures were reduced by 39.4% and 29.5%, respectively. Considering the convenience of field monitoring, it is suggested that the average strains at different layers can be used as characteristic parameters for estimating the health conditions of lining structures in service. The analysis results provide a practical reference for the design and health evaluation of water conveyance shield tunnels with composite linings.
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•Li is recycled from real spent LIBs leachate by electrodialysis with 99% purity.•Chelating agent improves the Li recovery rate from ca. 34.0% to ca. 63.0%•The feed flow type affects ...the Li recovery rate and purity.•A higher dosage of chelating agents achieves a higher Li recovery rate.•A leachate with a higher nickel ratio obtains a higher Li recovery rate.
Recovering lithium from industrial spent lithium-ion batteries (LIBs) leachate with an electrodialysis approach is still a challenge due to the complexity of the leachate, though some studies have been done on simplified synthetic LIBs solutions. This study successfully separates lithium ions from industrial spent LIBs leachate using an electrodialyzer equipped with a bipolar membrane module. Common chelating agents, including ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), L-glutamic acid (GLDA), and hydroxyethylethylenediaminetriacetic acid (HEDTA) are used to facilitate the recovery of lithium by forming complexes with other metal ions in the leachate. The effect of different chelating agents, their dosages, and varied fluid dynamics on lithium recovery rates are investigated. This approach has been proven to be suitable for lithium recovery from different LIBs industrial leachates including lithium cobalt (LCO), nickel rich (Ni-rich), and nickel manganese cobalt (NMC) spent LIBs black mass in this work. The highest purity and recovery rate of lithium under optimum conditions could achieve up to 99.43 % and 63.91 % respectively.
With the gradually increasing demand for solving the environmental pollution problem and energy crisis, efficient photocatalysts with superior charge carrier separation and transfer ability have ...attracted extensive research attention. Herein, n-type CdS-decorated p-Cu2O/n-ZnO nanorod arrays (CdS/Cu2O/ZnO NRAs), integrating the merits of both highly ordered structure and synergistic effect derived from dual p–n junctions, were successfully fabricated and further applied to photoelectrocatalysis. In this ternary nanocomposite, fast generation, separation, and transfer of charge carriers were achieved in the Cu2O/ZnO and Cu2O/CdS dual p–n junction regions due to their built-in electric field and appropriate band structures. Moreover, both highly ordered ZnO NRAs and compact CdS shell play the role of an electron collector and a transport channel that efficiently consumes the photoinduced electrons in the conduction band of Cu2O, which considerably reduces the recombination rate of charge carriers. As expected, the perfect cooperation of the three participators leads to the highest photoconversion efficiency of 2.61% at −0.275 V (versus saturated calomel electrode) and an incident photon-to-current conversion efficiency of 14.51% at 380 nm as well as the photoelectrocatalytic degradation ability of the optimized 30 min CdS/Cu2O/ZnO NRAs photoanode as compared to that of the Cu2O/ZnO and ZnO NRAs photoanodes. It is believed that the induced synergistic effect between dual p–n junctions and ZnO NRAs caused the superior performances of the CdS/Cu2O/ZnO NRAs photoanode, and this ternary material with a unique structure may present a new way of thinking for potential applications in the photoelectrochemistry field.
The ligand-free trifluoromethylation of arylboronic acids with a Ph(2)SCF(3)(+)OTf(-)/Cu(0) system has been carefully investigated. Aryl-, alkenyl- and heteroarylboronic acids with a variety of ...functional groups were suitable substrates for this reaction. It is suggested that a CuCF(3) species is formed under the reaction conditions.
▶ Fouling in ultrafiltration of tertiary effluent is inevitable. ▶ Sustainable operational condition mitigates fouling development. ▶ Chemically enhanced backwash is effective in fouling control. ▶ ...Effective cleaning of fouled membranes needs the cooperation effect of different chemicals. ▶ Economic comparisons are necessary in selecting operational conditions.
The present study investigated technical choices controlling fouling development of a pressure-driven ultrafiltration (UF) pilot plant filtering tertiary effluent and its corresponding economical aspects. Experimental results showed that although fouling potential of tertiary effluent (treated by slow sand filtration) is much lower than that of secondary effluent, fouling is inevitable and is greatly impacted by the applied operational conditions. Under certain filtration flux and backwash interval the trans-membrane pressure (TMP) can be effectively controlled. Operated at high flux and extended backwash interval, a stable performance of UF can also be maintained using chemically enhanced backwash (CEBW). The test of three kinds of chemicals demonstrates that oxidants are suitable reagents with respect to present effluent quantity. Different reagents were used to clean the fouled membrane. Their effects on permeability recovery were compared in relation to fouling removal mechanisms. Based on the empirical results, the total cost of UF under suggested operational conditions was compared.
To explore feasibility of 3D metal printing technology combined with virtual design proximal clavicle anatomical plate.
A 52-year-old male healthy volunteer was retrospectively selected to design ...proximal clavicle anatomical plate system by using Mimics15.01,NX12.0 and other software. STL data were input into 3D printer to print 1:1 clavicle model and proximal clavicle anatomical plate. The fit of the plate was tested in vitro and the accuracy of screw position was evaluated by imaging. Printing time of model,nail path design and fabrication time of the anatomical plate at proximal clavicle were recorded.
The 3D metal printing proximal clavicle anatomical plate fitted well to clavicle model,orientation of proximal clavicle locking screw was accurate,and X-ray and CT scan showed the screw position was good. Printing time of model,the time of nail path design,and the time of making anatomical plate of proximal clavicle were 120,15 and 300 min respectively.
The proximal clavicular anatomical plate system based o
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